1. Field of the Invention
This invention relates to absorbent pads and, more particularly, to such pads which are used in packaging of meat products for absorbing liquids leaking therefrom and to the method of fabricating such pads.
2. Description of the Prior Art
Absorbent pads particularly designed for packaging with meats, poultry and fish food products are used in food markets, poultry processing plants and the like to reduce product display costs and to provide a cleaner, more attractive product. These pads are generally wrapped with the food product on the underside thereof to absorb liquids which may "bleed" from the product. In poultry products, for example, it is customary to place the poultry parts of a given package in a molded shallow tray of foamed plastic or the like. One of these absorbent pads is placed in the bottom of the tray and the poultry parts are placed thereon. The complete package is then wrapped with clear polyethylene or the like.
In one example of the prior art, such pads are constructed of layers of highly absorbent cellulose tissue. As many as 16 such layers may typically be laminated in a single pad. Such a pad also includes a polyethylene backing layer which repels moisture so that it cannot draw the natural juices from the meat product, and to prevent leakage from the pad of the liquid which is absorbed in the tissue layers. This polyethylene backing layer presents a particular problem, however, in that while it serves its intended purpose as used in the meat package, it exhibits an unfortunate tendency to delaminate during normal use. This is because the absorbed liquid in the tissue laminations weakens the attachment of the polyethylene backing layer to the tissue layers. The then-wet polyethylene layer tends to adhere to the adjacent meat product with which it is wrapped. As a result, when the housewife or other user of the packaged meat product removes the outer wrapping and lifts the meat product from its tray or other package support member, the polyethylene backing layer frequently sticks to the meat, resulting in dripping while it is being handled and requiring the consumer to perform the unpleasant task of manually removing this layer from the surface of the meat product before the product can be placed in the pan or other cooking utensil in which it is to be prepared.
In one particular product of the prior art which has been designed to avoid this problem, a pad is fabricated out of pulp positioned between two layers of plastic, at least one of which has perforations to permit moisture to absorb into the pulp core of the pad. The pad is fabricated with a laminated plastic edge extending about its periphery, the pulp being contained in the pocket or island defined and surrounded by the laminated plastic edge. Since this lamination is essentially waterproof, it tends to avoid the delaminating forces resulting from liquid being absorbed into the absorbent portion of the pad. As a consequence, the plastic layer adjacent the meat product is unlikely to adhere to the meat when the meat is removed from its packaging. However, other problems arise. The pulp may escape the perforations in one of the plastic layers which are provided to permit liquid to be absorbed in the pulp, thereby contaminating the meat. Also, if a side seam is not completely closed, loose pulp dust may permeate an entire case in shipment, thereby ruining the contents for their intended purpose.
What is needed is some way of strengthening or reinforcing the pressure adhesion bonds that are formed in the absorptive pads of the first type described hereinabove. In the example described, these bonds are formed by running a plurality of toothed or serrated wheels, having relatively narrow edges at their periphery, over the pads as they are being run through the production line. The pads are typically formed by production line equipment which draws pluralities of individual cellulose tissue layers from a plurality of rolls mounted in the fabrication equipment so that a continuous strip of laminated pad material is formed. This is then slit lengthwise and cut transversely to form individual pads in the selected sizes. During this fabrication process, and before the transverse cuts are performed, the strip is run over rollers against which a plurality of toothed wheels bear to develop a plurality of broken lines of pressure contacts which lightly adhere the absorbent cellulose tissue layers together and to the polyethylene backing layer. In some instances, polyethylene backing layers are installed on both sides of the cellulose tissue lamination, in which case the adherence extends between the polyethylene backing layers through the compressed tissue layers. As stated above, however, the bond which is formed in this manner and the nature of the product are such that the liquids absorbed in the pad weaken this bond and permit the upper polyethylene backing layer to delaminate and be removed from the package by adherence with the meat product.